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/*! \file
    \brief Defines basic structures needed for implementing the warp-scoped
   phase of the epilogue. These quantities assume a 'column-major' arrangement
   of TensorOp instructions, of which a row-oriented slice is visible per
   iteration.
*/

#pragma once

#include "cutlass/matrix_shape.h"
#include "cutlass/layout/matrix.h"
#include "cutlass/gemm/gemm.h"

/////////////////////////////////////////////////////////////////////////////////////////////////

namespace cutlass {
namespace epilogue {
namespace warp {

/////////////////////////////////////////////////////////////////////////////////////////////////

/// Policy details related to the epilogue
template <typename WarpShape,  ///< shape of warp-level GEMM (concept:
                               ///< MatrixShape)
          typename InterleavedTileShape,  ///< shape of indivisible
                                          ///< instruction-level arrangement
                                          ///< (concept: GemmShape)
          typename ElementC,              ///< Accumulator layout
          typename Layout                 ///< target shared memory layout
          >
struct VoltaTensorOpPolicy;

/////////////////////////////////////////////////////////////////////////////////////////////////

/// Partial specialization for row-major
template <typename WarpShape_  ///< shape of warp-level GEMM (concept:
                               ///< GemmShape)
          >
struct VoltaTensorOpPolicy<WarpShape_, gemm::GemmShape<32, 32, 4>, half_t,
                           layout::RowMajor> {
    using WarpShape = WarpShape_;
    using InterleavedTileShape = gemm::GemmShape<32, 32, 4>;
    using ElementC = half_t;
    using Layout = layout::RowMajor;

    /// Shape of one warp-levelinstruction
    using InstructionShape = gemm::GemmShape<16, 16, 4>;

    /// Number of mma operations performed for one 32x32x4 interleaved tile
    using MmaIterations =
            MatrixShape<InterleavedTileShape::kM / InstructionShape::kM,
                        InterleavedTileShape::kN / InstructionShape::kN>;

    /// Number of 32x32x4 interleaved tiles performed to cover the warp-level
    /// GEMM shape
    using TileIterations =
            MatrixShape<WarpShape::kM / InterleavedTileShape::kM,
                        WarpShape::kN / InterleavedTileShape::kN>;

    /// Number of accumulator elements owned by each thread per Mma
    static int const kElementsPerMma = 8;
    static int const kRowsPerIteration = 16;

    //
    // Hard-coded constants regarding Tensor Operations
    //

    /// Number of accumulator elements stored per memory instruction to shared
    /// memory
    static int const kElementsPerAccess = 4;

    /// Number of accesses performed per interleaved tile
    static int const kAccessesPerInterleavedTile = 4;

    /// Total number of iterations needed to cover the entire tile
    static int const kIterations = TileIterations::kRow * 2;

    //
    // Derived types
    //

    /// Array type for aligned memory accesses
    using AccessType = AlignedArray<ElementC, kElementsPerAccess>;

    /// This is the fragment size produced by one access of the iterator.
    using Fragment =
            Array<ElementC, kElementsPerAccess * kAccessesPerInterleavedTile *
                                    TileIterations::kColumn>;

    /// This is the complete warp-level accumulator tile.
    using AccumulatorTile =
            Array<ElementC, TileIterations::kCount * MmaIterations::kCount *
                                    kElementsPerMma>;
};

/////////////////////////////////////////////////////////////////////////////////////////////////

/// Partial specialization for row-major
template <typename WarpShape_  ///< shape of warp-level GEMM (concept:
                               ///< MatrixShape)
          >
struct VoltaTensorOpPolicy<WarpShape_, gemm::GemmShape<32, 32, 4>, float,
                           layout::RowMajor> {
    using WarpShape = WarpShape_;
    using InterleavedTileShape = gemm::GemmShape<32, 32, 4>;
    using ElementC = float;
    using Layout = layout::RowMajor;

    /// Shape of one warp-levelinstruction
    using InstructionShape = gemm::GemmShape<16, 16, 4>;

    /// Number of mma operations performed for one 32x32x4 interleaved tile
    using MmaIterations =
            MatrixShape<InterleavedTileShape::kM / InstructionShape::kM,
                        InterleavedTileShape::kN / InstructionShape::kN>;

    /// Number of 32x32x4 interleaved tiles performed to cover the warp-level
    /// GEMM shape
    using TileIterations =
            MatrixShape<WarpShape::kM / InterleavedTileShape::kM,
                        WarpShape::kN / InterleavedTileShape::kN>;

    /// Number of accumulator elements owned by each thread per Mma
    static int const kElementsPerMma = 8;
    static int const kRowsPerIteration = 16;

    //
    // Hard-coded constants regarding Tensor Operations
    //

    /// Number of accumulator elements stored per memory instruction to shared
    /// memory
    static int const kElementsPerAccess = 2;

    /// Number of accesses performed per interleaved tile
    static int const kAccessesPerInterleavedTile = 8;

    /// Number of rows per interleaved tile
    static int const kRowsPerMmaTile = 2;

    /// Total number of iterations needed to cover the entire tile
    static int const kIterations = TileIterations::kRow * MmaIterations::kRow;

    //
    // Derived types
    //

    /// Array type for aligned memory accesses
    using AccessType = AlignedArray<ElementC, kElementsPerAccess>;

    /// This is the fragment size produced by one access of the iterator.
    using Fragment =
            Array<ElementC, kElementsPerAccess * kAccessesPerInterleavedTile *
                                    TileIterations::kColumn>;

    /// This is the complete warp-level accumulator tile.
    using AccumulatorTile =
            Array<ElementC, TileIterations::kCount * MmaIterations::kCount *
                                    kElementsPerMma>;
};

/////////////////////////////////////////////////////////////////////////////////////////////////

}  // namespace warp
}  // namespace epilogue
}  // namespace cutlass

/////////////////////////////////////////////////////////////////////////////////////////////////
